BirdAnalyst
Species · Washington · BBS 2025 Release · 1966–2024

Black Tern Population Trend in Washington

All statesWetland birds

Black Tern in Washington has fallen sharply: down 53% on the route-weighted index since 1970.

-53%Since 1970
12Routes In State
43Years

Notable Black Tern Trends in Washington

long arc declinecomputed index

Black Tern has fallen sharply in Washington: down 53% on the route-weighted index since 1970.

Black Tern Population Forecast in Washington

If the recent trend holds, Black Tern in Washington is projected to rise about 172% by 2026 — from 0.06 in 2021 to a central estimate of 0.16 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±488%, with 100% of held-out values landing inside the 95% band.

+172%Change by 2026
0.16Projected 2026 index
0.00–0.3995% range
±488%Backtest error
19682026
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20220.160.000.39
20230.160.000.39
20240.160.000.39
20250.160.000.39
20260.160.000.39

Black Tern Survey Routes in Washington

Routes recording Black Tern in Washington.
Turnbull Nwr420211993
Malden420121998
Brewster320001980
Ewan220191985
Ellensburg219981998
Moses Lake219901990
Curlew219921992
Twin Lakes220102010
Chewelah120122012
Harrington119801980
Reardan119901968
Potholes120061996

Black Tern Population Trend in Other States

californiacoloradoidahoillinoisindianaiowakansasmainemichiganminnesotamissourimontananebraskanevadanew-yorknorth-dakotaohiooregonsouth-dakotatexasutahwisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.